The present invention relates to a method and an apparatus for preparing a bonding wire for forming circuits on electronic components, in which in a removal station the bonding wire is subject to the action of at least one air flow oriented at right angles to the conveying direction for forming a wire reserve and is optronically detected or scanned by a sensor for controlling an electromotive drive operatively connected to the spool.
EP-A-0 130 104 discloses an apparatus for forming a bonding wire reserve, in which a bonding wire introduced through a first pipe socket or connection and subjected to the action of an air flow between two plates which can be folded to form a casing, passes out of the latter through a second connection. The wire reserve formed in a loop-manner by the air flow between the two plates is scanned by several spaced-apart sensors arranged successively in series and orthogonally to the passage direction on either side of the bonding wire. The values obtained are used for controlling an electromotive drive and for removing the bonding wire from the spool.
EP-A-0 226 126 discloses a wire removal apparatus used for the automatic laying of fine wires, in which the wire arranged in a loop chamber between two spaced plates is subject to the action of compressed air and, on reaching a given loop size, a correspondingly positioned pushbutton is operated and used for disconnecting the compressed air supply.
In conjunction with semiconductor technology, particularly for ultrasonically bonding wire connections of circuits on electronic components, such as chips or the like, the bonding wire (gold wire in the .mu.-range) is removed from a bonding wire spool mounted so as to rotate about its longitudinal axis. In the known apparatuses the problem exists that the bonding wire removed in the aforedescribed manner from the bonding wire spool is deflected and monitored by contacting corresponding elements, and consequently there is provided a corresponding control of the release of the bonding wire from the spool. This substantially mechanical deflecting and scanning often leads to the breaking of the bonding wire and therefore to an expensive maintenance and cost intensive stoppage of the complete apparatus. A further disadvantage of the known apparatuses is a complicated, time-consuming threading or insertion of the bonding wire.